In this video, we're going to talk about filtration as a physical method to controlling microbial growth. And so filtration is the process of using filters with pores that are incredibly small, small enough to actually physically remove microbes from either liquid or air. Now once again, the pores that are in the filter are incredibly small, and they're way smaller than the microbes themselves. And so the microbes, in relation to the pores, are way too large to pass through those pores of the filter. And therefore, the microbes are going to get trapped in the filter. And that is what separates the microbes from the liquid and air that they are in because the liquid and air can pass through the filter very easily, but the microbes are too large and cannot pass. They get trapped. And so filtration can be used to remove microbes from heat-sensitive liquids when heat is not an option. Now a very specific type of filter known as a high efficiency particulate air filter or a HEPA filter, for short, is a specific type of filter that will remove airborne particles and microbes from the air.
And so if we take a look at our image down below, notice that the left-hand side over here is focused on liquid filtration. And the right-hand side over here is focused on air filtration. And so focusing in on the left side first, notice that we have this apparatus right here, there is a vacuum pump with a flask here, and then there's this container at the top. And notice that the container at the top contains the contaminated liquid but it also contains the filter itself, which is horizontally here in orange color. And so the contaminated liquid is going to have microbes in it along with the liquid. And so, zooming into this region, you can see this over here, notice that the microbes are in green. So we can label these as the microbes. And the microbes are simply too large to pass through the pores of the filter. And so you can see the microbe filter again is here in orange, and there are some pores in it, but the microbes are too large to get through. However, the liquid itself is capable of getting through. And so the liquid is going to pass through this filter, but the microbes are going to get trapped in the filter itself. And so this separates the microbes from the liquid, and the liquid that gets through is going to be sterile liquid.
And so over here what we're showing you are some images of, some cells that are being trapped in a filter. And so here at the top, we're showing you Micrococcus luteus bacteria on a polycarbonate filter. And so notice that these bacterial cells that you see right here are simply too large to pass through these tiny, tiny little pores that are neighboring them. And so the microbes get trapped in the filter, but once again the liquid is capable of passing through. Down below, we're showing you some sperm cells on a polycarbonate filter and again, the sperm cells that you see here are simply too large to pass through these tiny little pores that you see all around them. Now over here on the right-hand side, again, we're showing you air filtration, and specifically you want to think about the HEPA filters, the high efficiency particulate air filters. And so HEPA filters are commonly used on airplanes to ensure that the air that you're breathing on airplanes is free of microbes that may be found in the atmosphere. Filter, or a HEPA filter for short.
And so this here concludes our brief lesson on filtration as a physical method to control microbial growth by physically removing microbes from liquids or air. And so we'll be able to get some practice applying these concepts moving forward and also learn about other physical methods of controlling microbial growth moving forward in our lesson. So I'll see you all in our next video.